Roger Tsien (1952 - 2016)

Roger Tsien, a Nobel Prize winner who helped develop a method to track cancer cells and follow the progress of Alzheimer’s disease, has died, according to The Associated Press. He was 64.

Tsien died Aug. 24 in Eugene, Oregon, according to a statement from the University of California at San Diego. UC San Diego Chancellor Pradeep Khosla said Tsien apparently died while on a bike trail, the San Diego Union-Tribune reported, but the cause of death had not been determined.

"Roger was an extraordinary man: kind, generous, gracious, and always the consummate scientist pushing the limits of his work to expand the possibilities of science," Khosla said. "He was a rare talent we cannot replace."

He shared the Nobel Prize in 2008 with Osamu Shimomura and Martin Chalfie. They were able to convert green fluorescent protein from a jellyfish into a research tool that could illuminate everything from brain cells to bacteria. Researchers use the fluorescent markers to track cellular processes.

"Our work is often described as building and training molecular spies," Tsien once said, according to the university. "Molecules that will enter a cell or organism and report back to us what the conditions are, what's going on with the biochemistry, while the cell is still alive."

"I've always been attracted to colors," Tsien told the Union-Tribune in 2008. "Color helps make the work more interesting and endurable. It helps when things aren't going well. If I had been born colorblind, I probably never would have gone into this."

"He was ahead of us all," Tsien's wife, Wendy, said in the university statement. "He was ever the adventurer, the pathfinder, the free and soaring spirit. Courage, determination, creativity, and resourcefulness were hallmarks of his character. He accomplished much. He will not be forgotten."

Tsien was born in New York City. He received degrees from Harvard and Cambridge.